Four-die tool and forging press

Abstract

The invention relates to a four-die press tool ( 1 ), comprising a lower die assembly ( 4 ) and an upper die assembly ( 6 ) displaceable relative thereto, comprising four rams ( 10, 11, 12, 13 ) spaced apart and supported on the lower die assembly ( 4 ) or the upper die assembly ( 6 ) and carrying forging dies ( 29 ), and a ring ( 20 ) on which are mounted the four rams ( 10, 11, 12, 13 ) concentrically around the central press axis ( 28 ) of the four-die press tool ( 1 ) in such a way that they can be displaced relative to the central press axis ( 28 ) whenever the upper die assembly ( 6 ) is moved relative to the lower die assembly ( 4 ), wherein protecting means ( 35 ) are mounted on the ring ( 20 ) to secure a workpiece in a centered position on a central predetermined position of the workpiece relative to the central press axis ( 28 ) independently of a workpiece manipulator.

The invention claimed is: 
     
       1. A four-die press tool adapted to be loaded by a manipulator with a workpiece, the tool comprising:
 a lower die assembly and an upper die assembly displaceable relative thereto and flanking a central press axis; 
 four rams spaced apart and supported on the lower die assembly and the upper die assembly; 
 respective forging dies carried on the rams; 
 a ring on which the four rams are mounted concentrically around the central press axis of the four-die press tool in such a way that they can be displaced relative to the central press axis whenever the upper die assembly is moved relative to the lower die assembly; and 
 protecting means on the ring, separate from and independent of the manipulator, and engageable with a workpiece for centering the workpiece in a predetermined position relative to the forging dies relative to the central press axis. 
 
     
     
       2. The four-die press tool according to  claim 1 , wherein the protecting means comprise a centering roller that centers the workpiece relative to the central press axis independently of the manipulator. 
     
     
       3. The four-die press tool according to  claim 1 , wherein the protecting means are mounted on the ring upstream and downstream of the rams along the central press axis. 
     
     
       4. The four-die press tool according to  claim 1 , wherein the protecting means are fixed relative to the central press axis. 
     
     
       5. The four-die press tool according to  claim 1 , wherein the protecting means are between the lower die assembly and the upper die assembly. 
     
     
       6. The four-die press tool according to  claim 1 , wherein at least one seat pocket is formed on the ring, a frame of the protecting means fitting in the pocket. 
     
     
       7. The four-die press tool according to  claim 2 , further comprising:
 a frame including a mount for the centering roller, the mount being removably fixed to the frame. 
 
     
     
       8. The four-die press tool according to  claim 2 , wherein the centering roller includes a body of rotation and includes on each end of the body at least one sealing groove that is concentric to the rotational axis of the body and that holds a metal seal ring. 
     
     
       9. The four-die press tool according to  claim 1 , wherein the four-die press tool is fixed by its upper die assembly to a movable crossbeam of the forging press. 
     
     
       10. The four-die press tool according to  claim 1 , wherein the forging dies are mounted so as to be fixed on but removable from the respective rams. 
     
     
       11. The four-die press tool according to  claim 1 , wherein the rams are mounted in an X-configuration centered on the axis. 
     
     
       12. An open-die forging press comprising a four-die press tool defining a central press axis for compressing and deforming a workpiece into an elongated semifinished product, and comprising at least one workpiece manipulator to deliver the workpiece to the four-die press tool, characterized by a four-die press tool according to  claim 1 .